Tuesday, November 18, 2008

Ceiling Fans and Water Storage

Another exchange between an Open House visitor and myself - great questions about my DC ceiling fans and my water tanks in the house...

Hello Christian.  

First, I want to thank you for the open house you held in early October.  That was most kind of you to open your house up to strangers.  My wife and I arrived on Saturday and were treated to a very interesting and informative tour you provided.  We both learned a lot and am so impressed on the sensible and logical steps you took in energy conservation and house construction--a fine job, well done!

I have been curious about a couple items.  If I remember correctly, the ceiling fans in your living room run on low voltage DC power, but I believe the rest of your power is converted to 120 VAC.  Why did you select the low voltage fans instead of 120 volt AC?

The water storage arrangement really caught my attention and makes a lot of sense.  Why did you put the tanks in the basement of the house instead of burying them in the ground below the frost level?

I didn't find the answers to the above questions on your website, however if the answer is listed please direct me there and save your time in answering.

Thanks again Christian.  That was so enjoyable to learn about your project and receive such a wonderful tour of your house.


Thank you very much for your kind words! I'm happy to answer your insightful questions for you.

Low Voltage Fans

Motors running on direct current, or DC, are inherently more energy efficient then AC motors. In the case of my fans they use only about between 18-19 W due to the aerodynamic blade design and the fact that they are DC-powered. The standard run-of-the-mill Hunter Douglas fans that I looked at seem to have a power consumption of about 150 or 180 W -- which is why I went with the DC powered fans to be able to "afford" cooling in the summer at a reasonable cost (e.g., letting the fans run from, say, 10 AM to Midnight would be 0.25 kWh vs. 2.5 kWh on an average daily budget of 3.5 - 5.0 kWh)

Looking at Energy-star certified fans again now, it seems that efficiency has greatly improved - on medium a energy-star certified Hunter fan uses approximately 6 Watts @ 5,000 cfm (cubic feet per minute) or 75 cfm per Watt. My fan produces 3,400 cfm at 18.7 W or 180 cfm per Watt. Running the fan 14 hours like the example above would use about 0.92 kWh.

Water Storage

There were three primary reasons for putting the tanks into the house: 

  1. I didn't really need that much more basement space. 
  2. Putting them into the house gave me easy access to the plumbing - if anything would ever go wrong or need replacement I can easily replace parts (versus the connections being buried)
  3. Three 2,500 tanks were only about $3,500 whereas a poured-in-place tank based on my research would have cost more like $7,500 to $10,000.

If I had to do it again, though, I would go with a ground-buried tank to avoid the mold issue.

Thank you again for your good questions and I hope that you will find my answers satisfactory. 


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Thursday, October 16, 2008

Living Room Temperatures in the Winter

A "neighbor" of mine shared his experience and send me this question:

"Winter is the time for talking about what is to be done next summer. What temp do you keep that house at during the winter ? I burn five to seven cords of wood, mostly elms that died the last summer, each winter. Stays 60F to 65F in the house."

Here's my reply:

My ultimate goal is to achieve 74+ °F all winter long while I'm in the house...and even just with passive solar and my masonry stove I frequently got the house back up to 72°. On cloudy, cold days the temperature might drop to 62 or 63 by 6 PM but by 8 PM it's back up in the upper 60s or lower 70s--with only one fire (using about 12-15 "smallish" logs). On weekends it's usually quite feasible to have the whole house warm (i.e., in the 70s) the whole weekend with four or five fires between Friday evening and Sunday evening. Overall I'm estimating that I used about four to five face cords or about two full cords per winter.

This winter, things will hopefully be even better. With help from friends I just installed my solar hot water collectors up on the roof (still need to do some leakage testing) and with that I'm ready to continue installation of my solar hot water and masonry stove heated radiant in-floor heating system. Which means that I will bring about 860 sq. ft. of 4" concrete up to a comfortable temperature (i.e., 72-75 surface temperature for a 65-67° "head-level" temperature). So I will have almost 300 cu ft. of concrete heated up - a lot of thermal mass that will be difficult to cool down once it's heated up.

Monday, October 13, 2008

Fridges and Refrigerators

Having heard about "A++" appliances (a program comparable to the Energy Star), out of curiosity I looked for energy-efficient fridges that are being sold in Germany.

One model that I found just after a few minutes of searching is a bottom-freezer fridge with about 12 cu ft of usable capacity (did you know that a fridge sold in the US as an "18 cu ft" fridge only has about 13 to 14 cu ft of usable space (source: Consumer Reports)?). Whereas a typical energy-efficient top freezer uses at least 370 kWh per year (that's what my fridge uses), this fridge uses only 211 kWh a year.

(For all those "off-gridders" out there - the Sunfrost RF19 (which has a little less usable capacity than 12 cu ft) uses about 300 kWh a year - at a cost of $2,700+...)


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Wednesday, September 24, 2008

Licht 'n Stein Featured on the National Solar Tour Homepage

The editors decided to feature Project Licht 'n Stein on the front page of the National Solar Tour 2008. Exciting!

(Although I feel bad because the picture does not show any renewable energy systems (okay, it shows rainwater collection and a passive solar design). Maybe I can send a new picture in this weekend showing my newly installed solar hot water panels)

See the pictures below:

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Licht 'n Stein Improvements, Fall 2008

Coming to Licht 'n Stein this fall...some long-awaited improvements: my solar hot water system and my photovoltaic system.

I've finally saved up enough energy (or converted some frustration into constructive energy) to start organizing the completion of two of my biggest still-awaiting-completion projects: My 3rd heating system (besides the Passive Solar Design and the Masonry Stove that kept me nicely warm for the past two winters) and the installation of a photovoltaic (converting sunshine into electricity)  array to complete my "off-the-grid" system.

Last Friday, September 19, Todd and DreamAcres' 2008 summer intern Andrew were instrumental in helping me to lift and install my two 40 sq. ft. solar hot water panels that had been standing in my backyard for the past 2 years. To be honest, I've been having nightmares the past two years trying to think about lifting those up...but Todd, with his great "barn raising conductor"  experience made it look and feel quite easy (except for the 30 seconds were both Andrew and I were up on the 30°/3:12 roof, trying to pull the 4 x 10 foot, 140 pound panels up onto the roof while the soles of our shoes (and we) were slowly sliding downward....but at last groaning (at least on my part) and muscle strength (on Andrew's part from a summer of farming organically) finally prevailed and the panels (one at a time) were up on the roof.

The installation on a standing seam steel roof was remarkably easy thanks to someone giving me the great tip (when I bought the panels) to buy some special clamps (S5!) that clamp on to the standing seam without pinching it (and of course eliminating the need to drill holes into my nice roof).

Although now that I think about it, the installation of the panels was the easy part...here's what's left to do:
  • Connect the 1/2" corrugated stainless steel pipes (flexible gas piping) to a 1" copper stub
    (actually from a picture of one of the houses on the national solar tour that is coming up, I got the idea of hiding/insulating my pipes in some PVC piping that I obviously would need to paint and then clamp to the roof)
    (Jonathan Allan pointed out that I would need a special torch for 1" piping)
    (Since I haven't done much pipe sweating I'm not sure how I will actually do it...Kirby offered to help, but with his shoulder I'd hate for him to have to climb up on that roof)
  • Order and install a 20W photovoltaic panel (more S5 clamps, I guess)
  • Figure out the whole plumbing design...with expansion tanks and all...then hook it all together
  • Finish my heating manifold
  • "Build" my heat storage tank and the heat exchangers
  • ...and much more

For my photovoltaic system my steps are
  • order the parts
  • dig out the whole, install the 6" pipe and order a concrete truck to fill it back in
  • install the Rack and the PV panels
  • install the charge controller and hook everything up
It'll be a busy fall!


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Tuesday, August 26, 2008

Residential Wind Generators

Hello dear Reader!

Here's another blog entry from the category of "questions answered in an eMail"

>What do you know about residential windmills?

Here’s what I know about residential windmills:
  • …that in Minnesota any energy produced by the generator that you don’t need can be fed back into the electrical grid, basically turning your meter backwards, i.e., you will earn the residential rate per kilowatt hour (kWh) of energy
  • …that the current electrical rates of about 10 cents per kWh are going up at a rate of 10% each year, basically doubling in price every 7-8 years.

  • …that a small generator (1kW Bergey, like mine) costs about $6-$8,000 to install, but will only produce about 2-5 kWh a day (i.e., the equivalent of 20-50 cents/day or $75-185 a year at the current electrical rates).
  • …that a larger generator (10kw Bergey) costs about $45,000 to install, and will produce about 20-65 kWh a day (i.e., the equivalent of $60 to $200 a month or $750 - $2,400 a year at the current rates)
  • ...that based on where I think I know you live, you have a wind potential of about 3-4 kWh/day with the small one and 35-50 kWh with the bigger one.

  • …that Garwin McNeilus in Dodge Center has had plans to design, construct, and sell 10k, 20k and 40k residential generators for $10k, $20k, and $40k, respectively, but has not gotten anywhere.

  • …that your best bet to do something for the environment is to spend some money on S.M.A.R.T. conservation (specific, measurable, attainable, relevant, and technology-driven). To make my house work, I first reduced my electrical usage from 30 kWh a day to 30 kWh per week – a reduction by almost 85%.
    If you’d like to learn more, check out my fledgling consulting company at http://consulting.lichtnstein.org

  • …that if your goal is self-sustainability, they work best in a hybrid system using photovoltaic (PV) cells and a wind generator.

  • …that they are beautiful to look at:

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Saturday, August 16, 2008

Frequently Asked Questions

Here is an interesting set of in-depth questions that I answered for a couple from Missouri that had heard about my house from one of their relatives:

>Is there a basement and what is it used for? Is it just to store the plastic water storage tanks?
Yes, the house has a full basement with 1,000 sq. ft. dedicated to living space and the rest to more utilitarian uses. The basement has three heated (radiant in-floor heat) rooms: a bedroom, a (future) home theater, and a (future) "studio" (a room with six walls of concrete). There is also a large storage space hallway. Other rooms are a "garden tools" room, a toilet/shower and utility sink, the utility room for the batteries, the on-demand water heater, the air-to-air exchanger, the hot water storage and the radiant in-floor heating manifold. The last room is the cistern room with the three 2,500 gal cisterns. The garden tools room has a walkout to the west, as does the utility room (with a double-wide door to allow for a skid steer or forklift to be driven in for replacement of the 2,000 pound battery (Twelve 166 pound cells).

>You said in your PowerPoint on the web that you used radiant floor heat. Is that connected to the masonry stove in any way?
Yes, once I have everything hooked up the radiant-floor heat will receive its heat from two sources: solar hot water panels on the roof (I already have the panels but haven't installed them) and two 1" heat exchanger pipes in the upper third of the masonry stove. That means I'll be able to take the heat of a fire the night before to heat up my bathroom the next morning using the radiant in-floor heat installed in the bathrooms. I can also take this heat to heat my basement, e.g., the home theater room.

>Can I assume that your floor is made of plywood, etc. and not concrete?
Actually to make the Passive Solar Design work, I needed a substantial amount of thermal mass on the main floor. So I have a poured-in-place concrete floor that has a total thickness of 16" with insulation. The concrete is 4" thick (with the radiant in-floor heating pipes embedded at the bottom of the 4" though in retrospect I should have spent some time trying to figure out how to lift them up a couple of inches so that they would float in the middle, since I fear that the latency (the time it takes from turning on the heat to actually reaching the desired temperature) will be quite high, but I haven't hooked everything up yet, so this concern is at this point just theoretical. The sub-floor for the half 2nd story is double-layered plywood - double-layered, so it accomodates the thin layer of gipkrete that I poured in the bathrooms for the radiant infloor heating, and I didn't want to have any uneven surfaces.

>Does the wind turbine require much maintenance?
No, the wind turbine does not require much maintenance and if I remember correctly an inspection is only required every five years. It's a tilt up tower, so it's not too complicated to do.

>How did you determine where to place the turbine?
The rule of thumb is that you don't want to have any trees or other obstructions higher than 30 feet below the wind turbine within 500 feet of the tower. The downside is that the further you place the turbine from the battery, the thicker (and more expensive) the electrical cable neeeds to be. I used a quite thick 1/0 aluminum cable for about $650 to run the 450 feet from the battery to the top of the tower. Basically I positioned the wind generator as far away and as highly elevated as possible. I went with an 84-foot tower since the 104-foot tower would have required me to get a conditional use permit for $400 and a hearing, but in general the higher you can go, the more favorable the wind conditions (and fewer turbulences). >Do you have a solar collector somewhere, because we could not see one on the roof, tho we couldn't see the roof on the north side of the house. I currently have no solar collectors installed (neither solar hot water nor photovoltaic electric) but everything is set up for it - I have the pipes already on the roof for the solar hot water and I have a cable in the ground for the photovoltaic panels.

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Friday, May 23, 2008

3D Home Software

Many people have asked me what software I used to design my home.

After some agonizing months with the home design package I bought, I settled on this two-step process:
  1. Design the floor plan using Microsoft Visio Professional's floor plan template. It's easy to make changes and the floor plan is what changes most frequently - and it's relatively easy to make changes. Besides, Visio supports "layers" so you can add electrical stuff and radiant in-floor heating layout and plumbing, etc.
  2. Once you're comfortable with the floorplan, fire up your 3D home software - I used "Punch Home Design" but based on my research all ~$100 packages have the same capabilities (and quirks). The most agonizing thing for me (which maybe has been resolved, who knows) was doing any kind of redesign, even as simple as moving a wall...it worked fine for a while, but quickly the model became "unstable".

Don't get me wrong - spending all these hours on sweating over how to put the design into the 3D modeling software was definitely worth it. I learned a lot from it and would go the same route again. I'd just brace myself for at least 3 iterations, i.e., starting from scratch in the 3D home design software for at least 3 times. You'll get faster, too.

If you have thoughts on or experience with 3D Home Design Software, use the comments feature below.